On Sat, Jan 17, 2009 at 3:13 AM, howard chen howachen@gmail.com wrote:

Are there any official documents related to the concurrent edit / locking model used in Wikipedia (DB)?

It's pretty simple. We use optimistic conflict resolution. No locking is used. If, when you go to save a page, someone else has modified the page in the time between when you started to edit and when you saved, an automatic merge is attempted. The merge will go through silently if the lines modified in previous revisions are different from in the submitted one. If the submitted revision modifies a line that was also modified since editing began, the user is informed of the conflict and asked to resolve it, with the full wikitext of the current version and the submitted one, and an appropriate diff.